Hydrophobic fiber and manufacturing method thereof

ABSTRACT

A hydrophobic fiber is provided which, obtained by modifying a natural fiber-containing fiber material without the use of fluorine compounds, has improved quick-dry properties, durability, wash-and-wear properties and antifouling properties while sufficiently maintaining the moisture absorption and desorption of the natural fibers; a manufacturing method of said fiber is also provided. By fixing a silicone elastomer film to at least part of the surface of a fiber material that contains cellulose fibers and/or animal fibers, the fiber is made into a hydrophobic fiber with a surface tension of less than 72 mN/m. The silicone elastomer film comprises methylhydrogen polysiloxane cross-linked with zinc stearate as the crosslinking agent.

TECHNICAL FIELD

The present invention relates to a hydrophobic fiber, which is obtained by modifying a natural fiber including at least one of a cellulose fiber or an animal fiber to render it hydrophobic, as well as to a manufacturing method for producing the same.

BACKGROUND ART

In general, a fiber obtained from a natural material such as a cellulose fiber or an animal fiber (hereinafter also referred to as a natural fiber) has an excellent moisture absorption/desorption property in comparison with synthetic fibers. However, because natural fibers absorb water and swell, they are inferior in terms of their rapid drying ability, durability, and shape stability (wash-and-wear ability), etc., after being washed. Further, natural fibers have a drawback in that they are inferior to synthetic fibers even in terms of their stain resistance (antifouling ability) with respect to oil stains.

Thus, in relation to a natural fiber, there is a desire to improve the physical properties thereof such as a rapid drying ability and durability, by modifying the natural fiber without impairing its intrinsic moisture absorption/desorption property. For example, in Japanese Laid-Open Patent Publication No. 08-134780, it is proposed to impart a water and oil repellent property to wool in a natural fiber. More specifically, a water repellent and oil repellent coating film is formed by applying in this order through adsorption a polysiloxane-based resin such as dimethylpolysiloxane or the like, and a fluorine compound such as a polytetrafluoroethylene resin or the like with respect to a wool fiber on which an oxidation treatment was performed.

SUMMARY OF INVENTION

However, in this case, since a sufficient bonding force between the wool fiber and the coating film cannot be obtained, and the coating film tends to fall off easily due to washing or the like, it is difficult to obtain a water and oil repellent property that exhibits sufficient washing durability. Further, when a fluorine compound is used, the moisture absorption/desorption property of the wool fiber tends to be lowered, and therefore, there is a concern that a feeling of stuffiness or mugginess or the like may occur when the wool fiber is worn. Furthermore, in consideration of their influence on the environment and the like, from the standpoint of further enhancing safety, it is preferable to avoid the use of fluorine compounds.

The present invention has been devised taking into consideration the aforementioned problems, and has the object of providing a hydrophobic fiber and a manufacturing method for producing the same, in which, by modifying a fiber material containing a natural fiber without using a fluorine compound, a rapid drying ability, durability, a wash-and-wear ability, and an antifouling ability thereof are improved while maintaining a sufficient moisture absorption/desorption property of the natural fiber.

In order to achieve the above-described object, the present invention is a hydrophobic fiber, which is rendered hydrophobic by modifying a fiber material containing at least one of a cellulose fiber or an animal fiber, the hydrophobic fiber being characterized in that a silicone elastomer film having methylhydrogen polysiloxane crosslinked with zinc stearate as a crosslinking agent is affixed to at least a portion of a surface of the fiber material, the hydrophobic fiber having a surface tension of less than 72 mN/m.

In the hydrophobic fiber according to the present invention, the silicone elastomer film is affixed to at least a portion of the surface of a fiber material containing a natural fiber including at least one of a cellulose fiber or an animal fiber (hereinafter referred to simply as a natural fiber). Consequently, the surface tension of the hydrophobic fiber is less than 72 mN/m, or in other words, is smaller than the surface tension of water. By providing the silicone elastomer film in this manner, the fiber material can be rendered hydrophobic without the use of a fluorine compound, and therefore, it is possible to prevent a decrease in the intrinsic moisture absorption/desorption property of the natural fiber.

Further, as described above, the hydrophobic fiber is rendered hydrophobic due to the silicone elastomer film, whereby it is possible to suppress swelling due to absorption of water during washing with water or the like, which is known to be a defect of natural fibers, and therefore, the rapid drying ability, durability, wash-and-wear ability, etc., can be improved. Further, by being brought close to the surface tension of sebaceous oil and cooking oil, which are likely to be a cause of oil stains in everyday life, the hydrophobic fiber exhibits an oil repellent property, and therefore, it is unlikely for oil stains to become adhered thereto, and the antifouling ability can also be improved.

Furthermore, since the silicone elastomer film can freely expand and contract in following relation with deformation of the fiber material, it is possible to maintain the state in which the silicone elastomer film is firmly affixed to the surface of the fiber material. Consequently, even in the event that frictional forces or the like are applied to the hydrophobic fiber in water or in a chemical cleaning agent when washing or dyeing is performed, it is possible to prevent the silicone elastomer film from peeling off from the surface of the natural fiber, and the silicone elastomer film itself is superior in terms of its durability.

As described above, the hydrophobic fiber is capable of improving a rapid drying ability, durability, a wash-and-wear ability, and an antifouling ability, etc., while also providing a moisture adsorption/desorption property superior to that of the original natural fiber, and in addition, is capable of maintaining the state in which such physical properties are enhanced over a prolonged period. Hence, compared to an untreated natural fiber, the amount of water used during washing of the hydrophobic fiber with water can be reduced, which is also preferable from the standpoint of the environment.

Further, the above-described silicone elastomer film is affixed to the fiber material mainly by a mechanical action such as an anchor effect or the like. Stated otherwise, the majority of the functional groups in the natural fiber exist in a state in which chemical bonds such as covalent bonding are not formed with the silicone elastomer film. Therefore, when the hydrophobic fiber is dyed, the functional groups in the natural fiber and the dye are capable of reacting sufficiently with each other, and dying with the dye can be performed suitably while avoiding color unevenness. Stated otherwise, the hydrophobic fiber is excellent in terms of its ability to be dyed, and piece dyeing thereof can be performed easily.

In the above-described hydrophobic fiber, the silicone elastomer film preferably contains conductive fine particles made of an n-type semiconductor containing zinc oxide as a principal component. The conductive fine particles absorb ultraviolet rays and both absorb and reflect infrared rays. On the other hand, the conductive fine particles transmit visible light. Accordingly, by the conductive fine particles being contained within the silicone elastomer film, it is possible for an ultraviolet shielding function and an infrared shielding function to be added to the hydrophobic fiber without inhibiting the development of color therein. In addition, since conductivity can be suitably added to the hydrophobic fiber, electrostatic charging is prevented, and generation of static electricity can effectively be avoided. Furthermore, excellent deodorizing and antibacterial properties can be added.

Further, generally, a wearer of clothing tends to experience a feeling of irritation from the clothing due to static electricity generated on the surface or the like of the clothing acting on the open pores, or by coming into contact with a fiber that possesses low flexibility. On the other hand, the conductive fine particles which mainly contain zinc oxide possess an astringent action. Accordingly, it is possible to suppress opening of the pores of a wearer of clothing or the like made from a hydrophobic fiber containing the conductive fine particles. Furthermore, in such a hydrophobic fiber, as described above, in addition to preventing the generation of static electricity due to the conductive fine particles, the hydrophobic fiber exhibits excellent flexibility due to the presence of the silicone elastomer film. Combined with this aforementioned feature, it is possible to reduce irritation to the wearer.

Further still, in the hydrophobic fiber, the conductive fine particles are contained within the silicone elastomer film which is firmly affixed to the fiber material in the manner described above. Consequently, since the conductive fine particles are firmly supported on the surface of the fiber material, the aforementioned functions that are added by the conductive fine particles are prevented from being reduced due to washing or the like of the hydrophobic fiber, and the sustainability of such functions is superior.

Further, the present invention is characterized by a hydrophobic fiber manufacturing method for obtaining a hydrophobic fiber by modifying a fiber material containing at least one of a cellulose fiber or an animal fiber, comprising the steps of immersing at least a portion of the fiber material in a mixed solution obtained by mixing zinc stearate into an aqueous dispersion in which silicone elastomer particles containing methylhydrogen polysiloxane as a principal component are dispersed, and obtaining the hydrophobic fiber having a surface tension of less than 72 mN/m by affixing a film shaped silicone elastomer in which the particles are crosslinked using the zinc stearate as a crosslinking agent to at least a portion of a surface of the fiber material.

Through the process steps described above, it is possible to obtain the hydrophobic fiber by firmly affixing the silicone elastomer film to the surface of the natural fiber. Due to such a silicone elastomer film, the surface tension of the fiber material can be made less than the surface tension of water, and the fiber material can be rendered hydrophobic without using a fluorine compound. Therefore, swelling of the natural fiber can be suppressed without impairing the excellent absorption/desorption property of the natural fiber, and thus the rapid drying ability, durability, wash-and-wear ability, etc., can be improved. Further, since the surface tension of the fiber material can be brought close to the surface tension of sebaceous oil and cooking oil, and an oil repellent property can be imparted to the hydrophobic fiber, it is unlikely for oil stains to become adhered thereto, and the antifouling ability can also be improved. Furthermore, due to its elasticity, since the silicone elastomer film can freely expand and contract in following relation with deformation of the natural fiber, it is possible to maintain the state in which the silicone elastomer film is firmly affixed to the surface of the natural fiber. Consequently, it is possible to maintain the state in which the rapid drying ability, durability, wash-and-wear ability, and the antifouling ability, etc., are enhanced over a prolonged period.

In the above-described hydrophobic fiber manufacturing method, there are preferably further included the steps of adding and causing to be contained in the mixed solution conductive fine particles made of an n-type semiconductor containing zinc oxide as a principal component, and obtaining the hydrophobic fiber having the conductive fine particles supported on the surface thereof. Due to the conductive fine particles, without inhibiting the development of color in the hydrophobic fiber, it is possible to obtain a hydrophobic fiber having an ultraviolet ray shielding function and an infrared shielding function. Furthermore, the hydrophobic fiber exhibits excellent deodorizing and antibacterial properties. Further, it is possible to prevent the generation of static electricity by preventing electrostatic charging, and due to the astringent action, it is possible to suppress the opening of pores of a wearer of clothing or the like made from the hydrophobic fiber. In addition, since the hydrophobic fiber exhibits excellent flexibility, in accordance with this feature, it is possible to reduce irritation to the wearer. The above-described functions which are added by the conductive fine particles are also superior in terms of their ability to be sustained. This is because the conductive fine particles are firmly supported on the surface of the fiber material by being contained within the silicone elastomer film.

In the hydrophobic fiber of the present invention, by affixing the silicone elastomer film having methylhydrogen polysiloxane crosslinked with zinc stearate as a crosslinking agent to the surface of the fiber material, the surface tension of the hydrophobic fiber becomes less than 72 mN/m. More specifically, since the natural fiber can be rendered hydrophobic without using a fluorine compound, swelling of the natural fiber can be suppressed without impairing the excellent absorption/desorption property of the natural fiber, and thus, the rapid drying ability, durability, wash-and-wear ability, etc., can be improved. Further, since an oil repellent property can be imparted by bringing the surface tension of the fiber material close to the surface tension of sebaceous oil and cooking oil, it is unlikely for oil stains to become adhered thereto, and the antifouling ability can also be improved.

Furthermore, due to its elasticity, since the silicone elastomer film can freely expand and contract in following relation with deformation of the natural fiber, it is possible to maintain the state in which the silicone elastomer film is firmly affixed to the surface of the natural fiber. Consequently, it is possible to maintain the state in which the rapid drying ability, durability, wash-and-wear ability, and the antifouling ability, etc., are enhanced over a prolonged period.

DESCRIPTION OF EMBODIMENTS

A preferred embodiment of a hydrophobic fiber according to the present invention will be presented and described in detail below in relation to a manufacturing method for manufacturing the same.

The hydrophobic fiber according to the present invention is obtained by modifying a fiber material containing a natural fiber including at least one of a cellulose fiber or an animal fiber. More specifically, the natural fiber may contain only a cellulose fiber, only an animal fiber, or both of a cellulose fiber and a natural fiber. In addition to the aforementioned natural fiber, a synthetic fiber may be contained in the fiber material.

The form of the fiber material is not particularly limited, and examples thereof may include cotton ball, tow, filaments, slivers, yarn, a non-woven fabric, a woven fabric, a knitted fabric, a towel, or the like.

As representative cellulose fibers, there may be cited cotton which is a natural plant fiber. Further, the cellulose fibers may also be hemp fibers such as ramie, linen, hemp, jute, manila hemp, sisal hemp, or the like. Further, the cellulose fiber may be composed of a so-called regenerated fiber obtained by dissolving natural cellulose in a predetermined solvent and then molding it into a fibrous form. Specific examples of this type of regenerated fiber include rayon, polynosic, cupra, and Tencel (registered trademark of Lenzing AG, Austria).

On the other hand, as representative examples of animal fibers, there may be cited silk, wool, or animal hair fibers. Specific examples of animal hair fibers include alpaca, mohair, angora, cashmere, camel, vicugna, and the like.

As examples of synthetic fibers, there may be cited polyester, polyurethane, aliphatic polyamide-based fibers (including 6-nylon and 6,6-nylon), aromatic polyamide-based fibers, and the like.

The ratio of the cellulose fibers, the animal fibers, and the synthetic fibers in the fiber material (hydrophobic fiber) is not particularly limited, and can be set to any desired ratio.

The hydrophobic fiber is constituted by affixing a silicone elastomer film having methylhydrogen polysiloxane crosslinked with zinc stearate as a crosslinking agent to at least a portion of the surface of the natural fiber within the fiber material.

Due to the silicone elastomer film, the surface tension of the hydrophobic fiber is adjusted to be less than 72 mN/m, and more preferably, is adjusted to be less than or equal to 35 mN/m. Consequently, it can be made difficult for water having a surface tension of 72 mN/m, or sebaceous oil or cooking oil having a surface tension of approximately 35 mN/m to permeate into the hydrophobic fiber.

Moreover, the surface tension can be determined by way of a so-called Dupont method. More specifically, initially, twelve types of mixed reagents having different concentrations from each other are prepared by mixing isopropyl alcohol (IPA) and distilled water. These twelve types of mixed reagents are classified into twelve grades from a 1st grade through a 12th grade according to the mixing ratios shown in Table 1. In Table 1, there is also shown together therewith surface tensions for each of the grades.

The surface tension of the measurement samples can be determined by dropping the mixed reagents onto the measurement samples in order from a small grade number to a large grade number, for example. More specifically, dropping of the mixed reagents is carried out five times, in a manner so that the diameter of the mixed reagent on the measurement samples by one dropping thereof is roughly 3 mm. After being left standing for 10 seconds, the grade number of the mixed reagent in which two or three droplets are left remaining in the form of droplets is determined. Thereamong, the surface tension of mixed reagents for which the grade number thereof is maximum can be recognized as being the surface tension of the measurement sample.

Stated otherwise, when the surface tensions of a solid and a liquid are compared, in the case that the surface tension of the liquid is large, the liquid is easily repelled by a solid. Accordingly, with the hydrophobic fiber according to the present embodiment, in which the surface tension is adjusted to be less than or equal to 35 mN/m, the mixed reagent is maintained in droplet form when the first grade through the third grade mixed reagents are dropped thereon.

TABLE 1 Volume % Distilled Surface Tension Grade IPA Water (mN/m) 1 2 98 59.0 2 5 95 50.0 3 10 90 42.0 4 20 80 33.0 5 30 70 27.5 6 40 60 25.4 7 50 50 24.6 8 60 40 23.8 9 70 30 23.1 10 80 20 22.3 11 90 5 21.5 12 100 0 20.8

Further, the silicone elastomer film preferably contains conductive fine particles made of an n-type semiconductor containing zinc oxide as a principal component. More specifically, the conductive fine particles are made from an n-type semiconductor in which zinc oxide is doped with a trivalent metal. From the standpoint of improving conductivity, as the trivalent metal, a metal doped with at least one of aluminum and gallium can be suitably used.

Further, from the standpoint of improving conductivity, it is preferable that the average particle diameter of primary particles of the conductive fine particles lies within a range of roughly 100 to 200 nm, and the average particle diameter secondary particles thereof lies within a range of roughly 4 to 5 μm. The average particle diameter can be measured with a commercially available particle size analyzer or the like, and for example, can be set to a particle diameter at an integrated value of 50% (D50) in a particle size distribution obtained by a laser diffraction/scattering method.

A process of obtaining the hydrophobic fiber which is configured basically in the manner described above will be described in relation to a manufacturing method according to the present embodiment.

First, particles of a silicone elastomer containing methylhydrogen polysiloxane as a principal component thereof are dispersed in an aqueous dispersion medium such as water to thereby prepare an aqueous dispersion liquid. A commercially available product such as “Light Silicone P-316” (trade name) (manufactured by Hokko Chemicals Co., Ltd.) or the like can be used as this type of methylhydrogen polysiloxane. Further, the aqueous dispersion liquid can also be obtained, for example, by mixing the aforementioned methylhydrogen polysiloxane together with a silicone emulsion at an appropriate concentration. A commercially available product such as “X-51-1318” (trade name) (a silicon emulsion manufactured by Shin-Etsu Chemical Co., Ltd.) can be used as this type of silicone emulsion. Moreover, the aqueous dispersion may be prepared solely from particles of a silicone elastomer containing methylhydrogen polysiloxane as a principal component thereof, and an aqueous dispersion medium such as water, without containing a silicone emulsion.

Zinc stearate is mixed as a crosslinking agent in the aqueous dispersion liquid to thereby obtain a mixed solution. A commercially available product such as “F-12E” (trade name) (manufactured by Hokko Chemicals Co., Ltd.) or the like can be used as this type of zinc stearate. In the case of obtaining a silicone elastomer film containing conductive fine particles, the conductive fine particles are further dispersed in the mixed solution. A commercially available product such as “Z-SDN” (a 25% dispersion of conductive zinc oxide manufactured by Satoda Chemical Industrial Co., Ltd.) or the like can be used as the conductive fine particles.

An anionic softening agent, for example, may be further added to the mixed solution as a modifying agent for adjusting the surface tension of the finally obtained hydrophobic fiber. In other words, the surface tension of the hydrophobic fiber can be appropriately adjusted, for example, by adjusting the degree to which the silicone elastomer particles undergo crosslinking due to such a modifying agent. A commercially available product such as “Hisofter ATS-2” (trade name) (manufactured by Meisei Chemical Works, Ltd.) can be used as this type of modifying agent.

Further, in regards to the mixed solution, the concentrations of each of the silicone elastomer particles, the zinc stearate, the conductive fine particles, and the modifying agent may be appropriately adjusted according to the material and form, and the shape and dimensions of the fiber material, so that the surface tension of the fiber material becomes less than 72 mN/m, and more preferably, less than or equal to 35 mN/m.

After the fiber material containing the natural fibers is immersed in the thus prepared mixed solution, the liquid is wrung out from the fiber material. Thereafter, the silicone elastomer particles are crosslinked with zinc stearate as a crosslinking agent, by carrying out a heating treatment or the like with respect to the fiber material on which a drying treatment was performed. The heating treatment can be carried out using existing heating equipment such as a heat setter, for example.

Consequently, a silicone elastomer film is formed, and the film can be firmly affixed to the surface of the natural fiber primarily by an anchor effect. As a result, a hydrophobic fiber is obtained having a surface tension of less than 72 mN/m.

In the hydrophobic fiber obtained through the above process, by providing the silicone elastomer film, the hydrophobic fiber is rendered hydrophobic without the use of a fluorine compound, and therefore, it is possible to prevent a decrease in the intrinsic moisture absorption/desorption property of the natural fiber. Further, with the hydrophobic fiber, it is possible to suppress swelling due to absorption of water during washing with water or the like, which is known to be a defect of natural fibers, and therefore, the rapid drying ability, durability, wash-and-wear ability, etc., can be improved. Further, by being brought close to the surface tension of sebaceous oil and cooking oil, which are likely to be a cause of oil stains in everyday life, the hydrophobic fiber exhibits an oil repellent property, and therefore, it is unlikely for oil stains to become adhered thereto, and the antifouling ability can also be enhanced.

Furthermore, since due to its elasticity, the silicone elastomer film can freely expand and contract in following relation with deformation of the fiber material, it is possible to maintain the state in which the silicone elastomer film is firmly affixed to the surface of the fiber material. Consequently, for example, even in the event that frictional forces or the like are applied to the hydrophobic fiber in water or in a chemical cleaning agent when washing or dyeing is performed, it is possible to prevent the silicone elastomer film from peeling off from the surface of the fiber material.

Accordingly, the hydrophobic fiber is capable of improving a rapid drying ability, durability, a wash-and-wear ability, and an antifouling ability, etc., while also providing a moisture adsorption/desorption property superior to that of the original natural fiber, and in addition, is capable of maintaining the state in which such physical properties are enhanced over a prolonged period. Hence, compared to an untreated natural fiber, the amount of water used during washing of the hydrophobic fiber with water can be reduced, which is also preferable from the standpoint of the environment.

Further, the silicone elastomer film is affixed to the fiber material mainly by a mechanical action such as an anchor effect or the like. Stated otherwise, the majority of the functional groups in the natural fiber exist in a state in which chemical bonds such as covalent bonding are not formed with the silicone elastomer film. Therefore, when the hydrophobic fiber is dyed, the functional groups in the natural fiber and the dye are capable of reacting sufficiently with each other, and dying with the dye can be performed suitably while avoiding color unevenness. Stated otherwise, the hydrophobic fiber is excellent in terms of its ability to be dyed, and piece dyeing thereof can be performed easily.

As a result, it is possible to stock the hydrophobic fiber in an undyed and unsewn condition, to carry out dying on the basis of information of fashionable colors collected immediately prior to sale thereof, and to directly perform sewing or the like thereon to quickly result in a textile product. More specifically, it is possible to provide commercial products in which rapidly changing fashionable colors and patterns are accurately captured in a short delivery period, and to reduce defective inventory and make effective use of resources, and hence, to reduce the cost of sewn products in which the hydrophobic fiber is used.

Further, when the conductive fine particles are dispersed in the silicone elastomer film, the conductive fine particles can be firmly supported on the surface of the hydrophobic fiber. Therefore, falling off or separation of the conductive fine particles from the hydrophobic fiber due to washing, dyeing or the like can be effectively suppressed. Consequently, the functions indicated below can be further added to the hydrophobic fiber, and the effectiveness of such functions is not easily lowered even after washing of the hydrophobic fiber, and the functions exhibit suitable sustainability.

More specifically, the conductive fine particles absorb ultraviolet rays and both absorb and reflect infrared rays. On the other hand, the conductive fine particles transmit visible light. Accordingly, it is possible for an ultraviolet shielding function and an infrared shielding function to be added, without inhibiting the development of color in the hydrophobic fiber by the conductive fine particles. In addition, since conductivity can be suitably added to the hydrophobic fiber, electrostatic charging is prevented, and generation of static electricity can effectively be avoided. Furthermore, excellent deodorizing and antibacterial properties can be added.

Further, generally, a wearer of clothing tends to experience a feeling of irritation from the clothing due to static electricity generated on the surface or the like of the clothing acting on the open pores, or by coming into contact with a fiber that possesses low flexibility. On the other hand, the conductive fine particles which mainly contain zinc oxide possess an astringent action. Accordingly, it is possible to suppress opening of the pores of a wearer of clothing or the like made from a hydrophobic fiber containing the conductive fine particles. Furthermore, in such a hydrophobic fiber, as described above, in addition to preventing the generation of static electricity due to the conductive fine particles, the hydrophobic fiber exhibits excellent flexibility due to the presence of the silicone elastomer film. Owing to this feature, it is possible to reduce irritation to the wearer.

Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the present embodiment, and various changes and modifications may be adopted therein without departing from the scope of the invention.

For example, a hydrophobic fiber in which a silicone elastomer film that does not contain conductive fine particles is affixed to the surface thereof may be obtained from an aqueous dispersion in which the conductive fine particles are not mixed therein.

EXAMPLES

Hereinafter, the present invention will be described in detail with reference to various examples thereof. However, the present invention is not limited to such examples.

Descriptions will be given of inventive examples of hydrophobic fibers, which are obtained by forming on the following fiber materials a silicone elastomer film containing conductive fine particles, or a silicone elastomer film that does not contain conductive fine particles. More specifically, a fiber material made from a material A of 100% cotton was used in the states of knitted fabrics A1 and A2, and a woven fabric A3. The knitted fabric A1 was a moss stitch knitted fabric prepared using No. 40 single yarn at 26-gauge, 26 inches. The knitted fabric A2 was a plain stitch knitted fabric prepared using No. 30 single yarn at 38-gauge, 67 inches. The woven fabric A3 was a plain weave (broad) fabric with 120 warp yarns per inch and 60 weft yarns per inch.

As the form of the fiber material, a woven fabric B1 is a plain weave (Ox) with 116 warp yarns per inch of 100% cotton yarns prepared using No. 40 single yarn, and 68 weft yarns per inch in which cotton and linen are blended at a 50:50 ratio. Stated otherwise, in the woven fabric B1, cotton and linen are blended at an 82:18 ratio.

The form of a fiber material composed of a material C in which cotton and Tencel are mixed at an 80:20 ratio was a 2/2 left twill woven fabric C1 with 126 warp yarns per inch, and 77 weft yarns per inch, prepared using No. 30 single yarn.

The form of a fiber material composed of a material D in which cotton and Tencel are blended at an 88:12 ratio was a moss stitch knitted fabric D1 prepared using 26 signal yarns at 26-gauge, 20 inches.

The form of a fiber material composed of a material E of 100% Viscose Rayon was a plain weave woven fabric E1 with 112 warp yarns per inch, and 94 weft yarns per inch, prepared using No. 40 single yarn.

Among the fiber materials, initially, desizing, scouring, and bleaching, dehydration, and drying were carried out on each of the knitted fabrics A1, A2, and D1. Further, initially, desizing, scouring, and bleaching were carried out on each of the woven fabrics A3, B1, C1, and E1. Next, in order to carry out a modifying treatment on the fiber material, initially, a mixed solution was prepared. In this instance, in the modifying treatment with respect to the test specimens A1, A2, B1, C1, and D1, a silicone elastomer film containing conductive fine particles was formed, and in the modifying treatment with respect to the test specimens A3 and E1, a silicone elastomer film containing no conductive fine particles therein was formed.

Therefore, in order to carry out the modifying treatment with respect to the test specimens A1, A2, B1, C1, and D1, a mixed solution was prepared so as to contain 20 g/L of “light silicone P-316” (methylhydrogen polysiloxane), 30 g/L of “X-51-1318” (silicone emulsion), 20 g/L of “F-12 E” (zinc stearate), and 80 g/L of “Z-SDN” (a 25% dispersion of conductive zinc oxide).

Further, in the modifying treatment with respect to the test specimen A3, a mixed solution was prepared so as to contain 20 g/L of “light silicone P-316” (methylhydrogen polysiloxane), and 20 g/L of “F-12E” (zinc stearate). In the modifying treatment with respect to the test specimen E1, a mixed solution was prepared so as to contain 50 g/L of “light silicone P-316” (methylhydrogen polysiloxane), and 50 g/L of “F-12E” (zinc stearate).

After each of the above-described fiber materials were immersed respectively in each of the mixed solutions, the solutions were wrung out from the fiber materials. As a result, a weight ratio (pickup) of the weight of the attached mixed solution to the weight of the fiber material before immersion was set to 70%. The fiber materials were subjected to a drying treatment at 150° C. for one minute and thirty seconds using a heat setter manufactured by IL SUNG MACHINERY, Co., Ltd.

Next, among the fiber materials after implementation of the drying treatment thereon, the knitted fabrics A1, A2, and D1 were subjected to a heat treatment at 170° C. for two minutes using the aforementioned heat setter in order to obtain hydrophobic fibers.

Further, concerning the other fiber materials (woven fabrics A3, B1, C1, and E1), they were subjected to a heat treatment at 170° C. for two minutes using a baking machine manufactured by SANDO ENGINEERING Co., Ltd., and thereafter, were subjected to a shrink-proofing process in order to obtain hydrophobic fibers.

The hydrophobic fibers which were obtained in the foregoing manner were used as inventive examples. On the other hand, fiber materials which were not modified in the above-described manner, and more specifically, which were not provided with the above-described silicone elastomer film, were used as comparative examples.

(Surface Tension)

Concerning each of the test specimens A1 to A3, B1, C1, and D1, excluding test specimen E1, from among the fiber materials of the inventive examples and the comparative examples, the surface tension before washing with water (zero times), the surface tension after washing was performed one time, the surface tension after washing was performed 25 times and the surface tension after washing was performed 50 times were measured. Further, concerning the test specimen E1, the surface tension before washing with water (zero times), and the surface tension after washing was performed 20 times were measured respectively.

Washing was carried out using a home electric washing machine VH-30S manufactured by Toshiba Corporation. More specifically, water and each of the measurement samples were inserted into a washing tub in a manner so that the measurement samples became 1 kg with respect to 30 L of water, or stated otherwise, so that the bath ratio was 1:30. At this time, the water temperature was set to 30° C. to 40° C. Further, the washing condition was set to a strong water flow condition, and washing was carried out one time for 15 minutes. Further, the surface tension was measured using the Dupont method described above. The results thereof are shown in Table 2.

TABLE 2 Surface Tension (mN/m) Inventive Example Comparative Example A1 Washing 0 33 ≥72 (times) 1 33 ≥72 25 42 ≥72 100 59 ≥72 A2 Washing 0 33 ≥72 (times) 1 42 ≥72 25 42 ≥72 100 50 ≥72 A3 Washing 0 33 ≥72 (times) 1 33 ≥72 25 42 ≥72 100 50 ≥72 B1 Washing 0 42 ≥72 (times) 1 42 ≥72 25 50 ≥72 100 59 ≥72 C1 Washing 0 33 ≥72 (times) 1 33 ≥72 25 42 ≥72 100 42 ≥72 D1 Washing 0 42 ≥72 (times) 1 42 ≥72 25 42 ≥72 100 50 ≥72 E1 Washing 0 50 ≥72 (times) 10 50 ≥72 20 50 ≥72

As shown in Table 2, the surface tension of the fiber materials according to the inventive examples was less than 72 mN/m both before washing and after washing. In contrast thereto, concerning the intrinsic surface tension of the fiber materials of the comparative examples, that is, the intrinsic surface tension of the fiber materials before being subjected to the modifying treatment, the surface tension thereof was greater than or equal to of 72 mN/m both before washing and after washing.

Accordingly, with the hydrophobic fiber, by providing the silicone elastomer film on the surface of the fiber material, the surface tension of the fiber material can be made less than the surface tension of water, and the hydrophobic fiber can suitably be made hydrophobic. Further, even in the event that frictional forces or the like are applied to the hydrophobic fiber in water at a time of washing, it is possible to prevent the silicone elastomer film from peeling off from the surface of the natural fibers. Consequently, even after repeated washing, it is possible for the aforementioned surface tension of the hydrophobic fiber to be maintained.

(Oil Repellent Property)

An oil repellency test was conducted on fiber materials according to the inventive examples in conformity with the AATCC 118-2002 method. In such a method, eight types of hydrocarbon solvents having different surface tensions are defined as test liquids, to which grade numbers are assigned in a manner so that the hydrocarbon solvents having larger surface tensions are assigned smaller grade numbers. For example, the test liquids are left standing for thirty seconds respectively at five locations, in order from those having smaller grade numbers, on the surface of the above-described fiber materials, from positions of about 0.6 cm in a height dimension, and so as to have sizes of about 5 mm in diameter. At this time, the oil repellent property of the surface of the fiber materials can be determined from the grade number of the test liquid, in which two or three droplets are left remaining in the form of droplets at the above-mentioned location.

The oil repellent properties, which were determined in the manner described above, of any of the fiber materials according to the inventive examples were of a grade number capable of sufficiently suppressing the permeation of cooking oils such as olive oil (surface tension 35.8 mN/m) and cottonseed oil (surface tension 35.4 mN/m) or the like. Therefore, since the hydrophobic fiber is brought close to the surface tension of sebaceous oil and cooking oil, which are likely to be a cause of oil stains in everyday life, and exhibits an oil repellent property, it is unlikely for oil stains to become adhered thereto, and the antifouling ability can also be improved.

(Rapid Drying Ability)

Concerning each of the test specimens A1 to A3, B1, C1, and D1, excluding test specimen E1, from among the fiber materials according to the inventive examples and the comparative examples, a rapid drying ability test as described below was performed in order to evaluate the rapid drying ability thereof.

First, the weight (dry weight of the fiber material after drying) of the test specimens A1 to A3, B1, C1, and D1 according to the inventive examples and the comparative examples after drying at 105° C. for two hours was measured. Next, the test specimens were washed in the same manner as in the above-described washing method, except that the washing time was set to 30 minutes, and the weight after dehydration was performed for 5 minutes (weight of fiber material after dehydration) was measured. Next, the test specimens were suspended and dried in a room at a temperature of 25° C.±1° C. and a humidity of 55%±5% (RH). At this time, the weight of the test specimens (weight of the fiber materials during suspension drying) was measured with each elapse of five minutes.

A difference between the weight of the fiber materials after drying and the weight of the fiber materials after dehydration is the weight (moisture weight after dehydration) of the moisture contained in the test specimens after dehydration. Therefore, the moisture content (%) of the test specimens when the suspension drying time is zero minutes is given by the formula, water content weight after dehydration (g)/weight of fiber material after drying (g). Further, the moisture content (%) of the test specimens each time that suspension drying is performed is given by the formula (weight of fiber material during suspension drying (g)−weight of fiber material after drying (g))/weight of fiber material after drying (g). Moisture content ratios of the test specimens of the inventive examples and the comparative examples which were calculated in this manner are shown in Table 3, together with the suspension drying time period.

TABLE 3 Suspension Drying Water Content Ratio (%) Time Period (minutes) Inventive Example Comparative Example A1 0 49.3 78.0 20 36.7 64.6 60 14.6 36.7 70 10.4 29.3 100 3.3 9.9 110 2.9 7.1 A2 0 38.7 81.9 5 35.4 77.8 30 17.9 57.3 50 8.5 42.3 70 6.0 28.0 100 2.5 10.2 110 3.5 6.8 A3 0 30.5 63.2 5 27.4 57.4 30 6.6 31.6 50 1.6 11.5 70 0.3 1.1 B1 0 44.8 68.5 5 37.7 61.6 10 31.5 55.1 20 21.6 42.6 30 11.9 30.3 40 4.1 17.9 50 0.9 7.1 C1 0 35.3 67.5 5 30.3 62.4 30 26.3 58.1 50 19.2 50.3 70 3.9 26.6 100 1.9 18.7 110 0.9 12.2 120 9.5 D1 0 44.0 60.5 5 41.8 58.1 30 28.6 45.8 50 18.6 35.0 70 10.9 25.9 100 2.9 13.2 110 1.7 9.8

As can be understood from Table 3, first, at a point in time when the suspension drying time period was zero minutes, that is, in a state in which only dehydration was performed, the water content ratio of the fiber materials according to the inventive examples was lower than the water content ratio of the fiber materials according to the comparative examples. Therefore, it can be understood that, with the hydrophobic fiber, at a time of washing in water, swelling by absorption of water is suppressed.

From the rapid drying ability test described above, there is further shown in Table 4 the suspension drying time periods (in minutes) required for the water content of the fiber materials according to the inventive examples and the comparative examples to decrease to 10%. Further, in Table 4, results are also shown together therewith by which a shortening ratio (Y/X)×100(%) was determined, in which the suspension drying time periods Y of the fiber materials according to the inventive examples were shortened with respect to the suspension drying time periods X of the fiber materials according to the comparative examples.

TABLE 4 Suspension Drying Time Period Required for Water Content Ratio Shortening Ratio to Decrease to 10% (minutes) of Drying Time Inventive Example Comparative Example Period (%) A1 70.0 100.0 30 A2 47.0 100.0 50 A3 25.0 52.0 50 B1 32.0 47.0 30 C1 62.0 117.0 50 D1 73.0 109.0 30

From Table 4, it can be understood that, with the fiber materials according to the inventive examples, the time periods required for drying are reduced by about 30% to 50% as compared with those of the fiber materials according to the comparative examples. Accordingly, with the hydrophobic fiber, it is possible to effectively improve the rapid drying ability in comparison with an untreated fiber material.

(Moisture Absorption/Desorption Property)

Concerning each of the test specimens A1 to A3, C1, and D1, excluding test specimens B1 and E1, from among the fiber materials according to the inventive examples and the comparative examples, the moisture absorption/desorption property (moisture content ratio) thereof was evaluated in conformity with the Boken method by the general incorporated association of the Boken Quality Evaluation Institute. More specifically, first, a test specimen of the aforementioned fiber material having a size of 20 cm² was exposed to an environment of 40° C. and 90% (RH) for 4 hours, whereby moisture was absorbed into the test specimen. Thereafter, moisture was released from the test specimen by exposing the test specimen for 4 hours under an environment of 20° C.×65% (RH). At this time, the weight (g) of the test specimen was measured with each elapse of one hour, and the moisture absorption/desorption property (moisture content ratio) (%) was obtained from such a change in weight. The results thereof are shown in Table 5. The environment of 40° C.×90% (RH) is a high temperature high humidity state which approximates the temperature and humidity in clothing when a person has performed light exercise. The environment of 20° C.×65% (RH) is a standard state approximating that of outside air temperature.

TABLE 5 Moisture Absorption/Desorption Property (Water Content Ratio) (%) Inventive Example Condition (RH) 40° C. × 90% 20° C. × 65% Time (h) 1 2 3 4 5 6 7 8 A1 7.9 9.6 10.4 11.0 7.5 7.0 6.9 6.9 A2 9.1 10.5 11.1 11.5 7.5 7.0 7.0 6.9 A3 8.3 9.8 10.5 11.0 7.3 6.7 6.6 6.6 C1 9.6 11.3 12.1 12.5 8.2 7.8 7.7 7.6 D1 7.2 9.3 10.3 11.1 8.5 8.0 7.7 7.5 Comparative Example Condition (RH) 40° × 90% 20° C. × 65% Time (h) 1 2 3 4 5 6 7 8 A1 8.0 9.5 10.3 10.8 7.4 7.1 7.0 7.0 A2 9.9 10.6 10.9 11.2 7.7 7.3 7.2 7.1 A3 8.9 10.2 10.8 11.1 7.1 6.9 6.9 6.8 C1 10.1 11.5 12.0 12.2 8.3 7.9 7.8 7.8 D1 7.9 10.1 11.0 11.5 8.7 8.1 7.9 7.8

From Table 5, it can be understood that the moisture absorption/desorption property of the fiber materials according to the inventive examples is approximately the same as that of the fiber materials of the comparative examples. More specifically, with the hydrophobic fibers, the intrinsic moisture absorption/desorption property of the fiber materials can be adequately maintained.

(Ultraviolet Cut Rate)

Among the fiber materials according to the inventive examples and the comparative examples, concerning the test specimens A1, A2, B1, and D1 on which the silicone elastomer film containing conductive fine particles was formed, an ultraviolet cut rate of the respective test specimens was evaluated using an ultraviolet-visible-near infrared spectrophotometer “UV-3150” (trade name) manufactured by Shimadzu Corporation. More specifically, in regard to the test specimens of the above-described fiber materials, the transmittance thereof at wavelengths of 220 nm to 400 nm was measured, and a value obtained by subtracting the obtained measurement value from 100 was defined as the ultraviolet cut rate (%). The results thereof are shown in Table 6.

TABLE 6 Ultraviolet Cut Rate (%) Inventive Example Comparative Example A1 88.2 82.9 A2 82.9 74.4 B1 80.6 72.1 D1 93.3 82.0

From Table 6, it can be understood that, with the fiber materials according to the inventive examples, higher ultraviolet cut rates are exhibited in comparison with those of the comparative examples. Specifically, with the hydrophobic fiber, ultraviolet rays can be effectively absorbed by the conductive fine particles contained within the silicone elastomer film.

(Infrared Absorption Ability)

In regards to each of the test specimens A1, A2, B1, C1, and D1 on which the silicone elastomer film containing conductive fine particles was formed, infrared absorption abilities of the inventive examples and the comparative examples were compared by the following method. Specifically, initially, each of the test specimens was placed in an opening of a box having an internal capacity of 60 ml, and having cork for heat insulation provided on a side wall thereof. Further, a thermocouple temperature sensor was disposed inside the box in which the test specimens were placed so that the distance from the test specimens was 2 mm. Next, from among both surfaces of the test specimens, a 100 W infrared light of a near-infrared ray lamp was irradiated from one surface of the test specimens on an opposite side from the thermocouple temperature sensor. As the near-infrared ray lamp, model number IR100/110V100WR manufactured by Toshiba Corporation was used, and the distance from the test specimens was 150 mm. Also, the temperature of the test room was set to 25° C.±2° C. and the humidity was set at 40%±5% RH.

In accordance with this setup, the temperature inside the box that was irradiated with infrared light through the test specimens was made to rise, and thus at this time, the change in temperature was measured over time with the thermocouple temperature sensor. Within the measurement results, the difference between the inventive examples and the comparative examples was taken in regard to each of the temperatures thereof after 15 minutes, 4 hours, and 8 hours from the initial irradiation by the near infrared ray lamp, and the infrared absorption ability of each was compared. The results thereof are shown in Table 7.

TABLE 7 Temperature (° C.) Irradiation Inventive Comparative Time Example Example Difference Al 15 minutes 42.5 44.4 −1.9 4 hours 44.2 46.2 −2.0 8 hours 44.2 46.1 −1.9 A2 15 minutes 43.2 45.5 −2.3 4 hours 43.8 46.1 −2.3 8 hours 44.0 46.2 −2.2 B1 15 minutes 42.1 44.6 −2.5 4 hours 43.5 45.9 −2.4 8 hours 42.7 45.3 −2.6 C1 15 minutes 43.5 45.3 −1.8 4 hours 43.6 45.5 −1.9 8 hours 44.8 46.5 −1.7 D1 15 minutes 43.8 46.0 −2.2 4 hours 45.1 47.4 −2.3 8 hours 45.5 47.7 −2.3

From Table 7, it can be understood that the rise in temperature due to infrared radiation was less with the fiber materials of the inventive examples than with the fiber materials of the comparative examples. Stated otherwise, with the hydrophobic fiber, it is possible to effectively absorb and reflect infrared rays. Further, from the fact that the effect of suppressing a rise in temperature due to infrared irradiation of the hydrophobic fiber is maintained even after the elapse of 8 hours from the initial irradiation with infrared rays, it can be understood that such an effect possesses excellent sustainability.

(Wash-and-Wear Ability)

A wash-and-wear ability evaluation test was performed on the fiber materials A1 according to the inventive example and the comparative example, and on the fiber material E1 according to the inventive example. This test was conducted at the general incorporated association of the Boken Quality Evaluation Institute.

In greater detail, first, three test specimens of 400 mm² were prepared from the aforementioned fiber materials. With respect thereto, washing and drying were carried out in conformity with the JIS L 1096 G method (JIS L 0217 103). More specifically, water and the measurement samples were inserted into a washing tub so that the bath ratio was 1:40. At this time, the water temperature was set to 40° C., and during washing, the detergent “Attack” (trade name) (a synthetic detergent manufactured by Kao Corporation) was added at an amount of 1 g/L. Further, the following washing conditions were employed: washing with a strong water flow for twelve minutes, drainage, centrifugal dehydration for two minutes, rinsing for two minutes, drainage, centrifugal dehydration for two minutes, rinsing for two minutes, drainage, and centrifugal dehydration for four minutes were carried out in this order to thereby complete one washing cycle. Then, after completion of washing, the wash-and-wear ability was evaluated after carrying out suspension drying in a manner so that the longitudinal direction of the test specimens was oriented along the vertical direction.

In regards to the fiber materials A1 according to the inventive examples and the comparative examples, the wash-and-wear abilities thereof were evaluated after washing was performed one time and after washing was performed five times, respectively. Further, in regards to the fiber material E1 according to the inventive example, the wash-and-wear ability thereof was evaluated after washing was performed one time and after washing was performed twenty times, respectively. The results thereof are shown in Table 8.

The wash-and-wear ability is an index representing the degree of wrinkles that remain after washing, and is evaluated by making a comparison with an evaluation replica prescribed by the AATCC TEST METHOD 124, and assigning a grade (1st grade through 5th grade) thereto. The higher the grade, the fewer amount of wrinkles that remain.

TABLE 8 Wash-and-Wear Ability (grade) Inventive Example Comparative Example A1 Washing 1 3.5 2.7 (times) 5 3.2 2.3 E1 Washing 5 3.5 (times) 20 3.3

From the results shown in Table 8, it can be understood that the fiber materials of the inventive examples had more superior grades in relation to the wash-and-wear ability in comparison with those of the fiber material of the comparative example, and even after repeated washing, it was possible to maintain the wash-and-wear ability at a grade of 3.2 or higher. Stated otherwise, with the hydrophobic fiber, it is possible to improve the wash-and-wear ability, and to enable the wrinkle cutting ratio (the degree to which wrinkles are removed) after washing to be greater than or equal to 50% in comparison with an untreated fiber material, and therefore, as a shape stabilizing process, a sufficient wash-and-wear ability can be demonstrated over a prolonged period.

(Bursting Strength)

The bursting strengths of each of the woven fabrics A3, B1, and D1 according to the inventive examples and the comparative examples were measured in conformity with the JIS L 1096 A method (Mullen type method). More specifically, initially, five test specimens each having a size of 15 cm×15 cm were collected. In addition, using a Mullen type bursting tester, with the surface of the test specimens facing upward, the test specimens were gripped by a clamp with uniform tension applied thereto. Pressure was applied to the test specimens from a rear side through a rubber film, and the strength A (kPa) at which the rubber film broke through the test specimens, and the strength B (kPa) of only the rubber film at a time of breakage thereof were measured. Then, the bursting strength Bs (kPa) was determined in accordance with the following equation (2), and the average value thereof was calculated as the bursting strength.

Bs=A−B  (2)

The bursting strength was calculated by carrying out the above-described measurement, for each of a condition in which the test specimens were left standing for 24 hours at 20° C. and 65% relative humidity, and a condition in which the test specimens were immersed in water and moistened so that the moisture content thereof became 100%. The results thereof are shown in Table 9.

TABLE 9 Bursting Strength (kPa) Inventive Example Comparative Example Dry Moist Dry Moist A1 318.5 303.8 298.9 303.8 A2 480.0 539.0 495.0 382.0 D1 564.0 686.0 461.0 588.0

From Table 9, it can be understood that, both in a dry condition and a moist condition, the fiber materials of the inventive examples exhibit a bursting strength which is substantially equivalent to or greater than that of the fiber materials of the comparative examples. Therefore, the hydrophobic fiber is also excellent in terms of its bursting strength.

(Tearing Strength)

The tearing strengths of each of the woven fabrics A3, B1, C1, and E1 according to the inventive examples and the comparative examples were measured in conformity with the JIS L 1096 D method (pendulum method). More specifically, initially, five test specimens each having a size of 63 mm×roughly 100 mm were collected. In addition, using an Elemendorf tearing strength tester, short sides of both ends in the longitudinal direction of the test specimens were gripped. Then, after having introduced a cut of 20 mm approximately in the center of the elongate side of the test specimens at a right angle to the elongate side, a load was applied so as to pull in opposite directions on both ends of the test specimens. In accordance with this method, the load (N) at the time that a remaining 43 mm of the wefts were torn was taken to represent the tearing strength in the longitudinal direction. By setting the elongate side of the test specimens in the longitudinal direction, it is also possible to measure the tearing strength in the transverse direction in the same manner as the tearing strength in the longitudinal direction.

The tearing strength was measured for each of a condition in which the test specimens were left standing for 24 hours at 20° C. and 65% relative humidity, and a condition in which the test specimens were immersed in water and moistened so that the moisture content thereof became 100%. The results thereof are shown in Table 10.

TABLE 10 Tearing Strength (N) Inventive Example Comparative Example Dry Moist Dry Moist A1 longitudinal 12.0 12.0 11.0 14.0 transverse 8.0 19.0 6.0 7.5 B1 longitudinal 59.0 50.0 40.0 60.0 transverse 38.0 51.0 16.0 37.0 C1 longitudinal 52.0 40.0 29.5 21.0 transverse 30.5 26.0 22.5 18.0 E1 longitudinal 16.2 15.2 11.2 8.0 transverse 14.0 12.8 8.4 6.0

From Table 10, it can be understood that the tearing strengths of the fiber materials of the inventive examples are greater than those of the fiber materials of the comparative examples, both in the longitudinal direction and in the transverse direction. Further, in the fiber materials of the comparative examples, the tearing strength at a time of being moist is reduced by roughly 30% compared to the tearing strength thereof at a time of being dry. In contrast thereto, with the fiber materials of the inventive examples, the rate of the decrease in the tearing strength at a time of being moist is on the order of roughly 10% compared to the tearing strength thereof at a time of being dry. More specifically, with the hydrophobic fiber, it is possible to improve the tearing strength in comparison with an untreated fiber material, and it is possible to maintain a high tearing strength even when moist. 

1. A hydrophobic fiber which is rendered hydrophobic by modifying a fiber material containing at least one of a cellulose fiber or an animal fiber; the hydrophobic fiber being characterized in that a silicone elastomer film having methylhydrogen polysiloxane crosslinked with zinc stearate as a crosslinking agent is affixed to at least a portion of a surface of the fiber material, the hydrophobic fiber having a surface tension of less than 72 mN/m.
 2. The hydrophobic fiber according to claim 1, wherein the silicone elastomer film contains conductive fine particles made of an n-type semiconductor containing zinc oxide as a principal component.
 3. A hydrophobic fiber manufacturing method for obtaining a hydrophobic fiber by modifying a fiber material containing at least one of a cellulose fiber or an animal fiber, comprising the steps of: immersing at least a portion of the fiber material in a mixed solution obtained by mixing zinc stearate into an aqueous dispersion in which silicone elastomer particles containing methylhydrogen polysiloxane as a principal component are dispersed; and obtaining the hydrophobic fiber having a surface tension of less than 72 mN/m by affixing a film shaped silicone elastomer in which the particles are crosslinked using the zinc stearate as a crosslinking agent to at least a portion of a surface of the fiber material.
 4. The hydrophobic fiber manufacturing method according to claim 3, further comprising the steps of adding and causing to be contained in the mixed solution conductive fine particles made of an n-type semiconductor containing zinc oxide as a principal component, and obtaining the hydrophobic fiber having the conductive fine particles supported on the surface thereof. 